1. **State the problem:** Solve the equation $3x^2 + 9x = -6$ by graphing the related function and finding its zeros.
2. **Rewrite the equation:** Move all terms to one side to set the equation equal to zero:
$$3x^2 + 9x + 6 = 0$$
3. **Define the function:** Let
$$y = 3x^2 + 9x + 6$$
4. **Find zeros of the function:** The zeros are the values of $x$ where $y=0$.
5. **Use the quadratic formula:** For $ax^2 + bx + c = 0$, the solutions are
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
Here, $a=3$, $b=9$, $c=6$.
6. **Calculate the discriminant:**
$$\Delta = b^2 - 4ac = 9^2 - 4 \times 3 \times 6 = 81 - 72 = 9$$
7. **Calculate the roots:**
$$x = \frac{-9 \pm \sqrt{9}}{2 \times 3} = \frac{-9 \pm 3}{6}$$
8. **Find each root:**
- For $+$:
$$x = \frac{-9 + 3}{6} = \frac{-6}{6} = -1$$
- For $-$:
$$x = \frac{-9 - 3}{6} = \frac{-12}{6} = -2$$
9. **Interpretation:** The graph of $y = 3x^2 + 9x + 6$ crosses the x-axis at $x = -1$ and $x = -2$. These are the solutions to the original equation.
**Final answer:**
$$x = -1, -2$$
Quadratic Zeros 9Cb721
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